Software Engineering for Students A Programming Approach

18 Chapter 1 ■ Software – problems and prospects
■ greater emphasis on trying to ensure that software is free of errors (verification).
■ incremental development, where a project proceeds in small, manageable steps
We will be looking at all of these ideas in this book. These solutions are not mutually
exclusive; indeed they often complement each other.
Verification, prototyping and other such techniques actually address only some of the
problems encountered in software development. A large-scale software project will comprise
a number of separate related activities, analysis, specification, design, implementation,
and so on. It may be carried out by a large number of people working to strict deadlines,
and the end product usually has to conform to prescribed standards. Clearly, if software
projects are to have any chance of successfully delivering correct software on time within
budget, they must be thoroughly planned in advance and effectively managed as they are
executed. Thus the aim is to replace ad hoc methods with an organized discipline.
One term that is used a lot these days in connection with software is the word quality.
One might argue that any product (from a cream bun to a washing machine) that
fulfills the purpose for which it was produced could be considered to be a quality product.
In the context of software, if a package meets, and continues to meet, a customer’s
expectations, then it too can be considered to be a quality product. In this perspective,
quality can be attained only if effective standards, techniques and procedures exist to be
applied, and are seen to be properly employed and monitored. Thus, not only do good
methods have to be applied, but they also have to be seen to be applied. Such procedures
are central to the activity called “quality assurance”.
The problem of producing “correct” software can be addressed by using appropriate
specification and verification techniques (formal or informal). However, correctness
is just one aspect of quality; the explicit use of project management discipline is a key
factor in achieving high-quality software.
Summary
We have considered a number of goals and problem areas in software development.
Generally, software developers have a bad image, a reputation for producing software
that is:
■ late
■ over budget
■ unreliable
■ inflexible
■ hard to use.
Because the problems are so great, there has been widespread talk of a crisis in software
production. The general response to these problems has been the creation of a
number of systematic approaches, novel techniques and notations to address the software
development task. The different methods, tools and languages fit within a plan
of action (called a process model). This book is about these approaches. Now read on.